Composite treatment agent for sewage treatment and preparation method thereof

Abstract

The invention discloses a composite treatment agent for sewage treatment and a preparation method thereof, and the composite treatment agent is prepared from the following raw materials in parts by weight: 50-60 parts of modified diatomite, 10-20 parts of zeolite powder, 10-20 parts of polyaluminum chloride, 10-20 parts of activated carbon, 5-10 parts of shell powder, 5-10 parts of polyacrylamide and 4-8 parts of lauryl sodium sulfate. According to the composite treatment, modified diatomite, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide and lauryl sodium sulfate are compounded and mixed according to a specific proportion, so that the obtained composite treatment agent has good adsorbability and can quickly and efficiently adsorb heavy metal ions in sewage; meanwhile, organic pollutants in sewage can be complexed, and the method has a good application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and particularly relates to a composite treatment agent for sewage treatment and a preparation method thereof. Background Art

[0002] Water is a precious natural resource and a necessary condition for human survival. At present, organic sewage, dye sewage, and heavy metal sewage in industrial wastewater account for a large proportion, and an efficient and reliable sewage treatment method is needed to treat them specifically.

[0003] Industrial sewage is a type of sewage with a relatively large proportion in modern society. With the development of industry, the discharge and recycling treatment of more and more industrial sewage need to be solved. Industrial sewage is different from domestic sewage. Industrial sewage contains many heavy metals, and industrial sewage pollutes the environment more seriously and threatens human health. Therefore, the treatment of industrial sewage is more important than the treatment of urban domestic sewage.

[0004] Currently, the common sewage treatment methods mainly include flocculation precipitation method, chemical oxidation method, biodegradation method, and adsorption method. Among them, the adsorption method has been proven to be able to rapidly reduce the content of heavy metals and organic pollutants in sewage. The adsorption method has been widely used in the treatment of dye sewage, petrochemical sewage, oil and gas field sewage, heavy metal sewage, and dye sewage. The adsorption method generally uses a porous adsorbent to adsorb and remove organic pollutants, heavy metal ions, dye pollutants, etc. in sewage; since the porous adsorbent used is a solid substance, in sewage treatment, it can adsorb and separate pollutants in sewage with relatively low sewage treatment energy consumption, and will not introduce new pollutants into the sewage; and it is easy to carry out solid-liquid separation after sewage treatment and will not cause secondary pollution to the environment, and has a good effect on the advanced treatment of wastewater. Therefore, the adsorption method has always been one of the mainstream methods for industrial wastewater treatment.

[0005] Chinese Patent Application CN114247419A discloses an adsorption material, a preparation method thereof, and an application thereof, which are mainly obtained by modifying a solid catalyst with alkali and lanthanum ions; the main components of the solid catalyst include: SiO 2 、Al 2 O 3 and Fe 3 O 4The raw material of the adsorption material is a Fischer-Tropsch synthesis waste catalyst, which can be reused as an adsorbent for wastewater treatment after modification. The adsorption cost is low, and it can effectively adsorb fluoride ions in coal chemical wastewater. However, this adsorbent only has a good adsorption effect on fluoride ions in wastewater, and the components of chemical wastewater are complex, including various harmful chemical substances, such as organic matter, heavy metals, organic solvents and other pollutants. These pollutants may affect the adsorption efficiency of the adsorbent. Chinese Patent Application CN107866208A discloses a composite sewage treatment agent based on modified diatomite, its preparation method and application. The composite sewage treatment agent is mainly prepared by mixing diatomite and a light yellow viscous sol. The preparation method of the composite sewage treatment agent includes the following steps: (1) activation of diatomite; (2) preparation of the light yellow viscous sol; (3) diluting the light yellow viscous sol and adding it to the activated diatomite, continuously stirring and filtering, and then drying the sample to obtain the composite sewage treatment agent. When the composite sewage treatment agent is put into sewage, under the condition that the pH of the sewage is 6, adsorb and stir for 30 minutes, and then stand for 1 hour to complete the sewage purification process. The composite sewage treatment agent of this invention is based on modified diatomite and composited with a light yellow viscous sol crosslinked by γ-polyglutamic acid and chitosan. The preparation method of this composite sewage treatment agent is simple, practical and convenient, with a short treatment time, low cost, good sewage treatment effect and stable indexes. However, it is impossible to see the treatment effect of this composite sewage treatment agent on heavy metal ions and organic pollutants in sewage from the specification of this invention.

[0006] Therefore, it is of great significance to develop a composite treatment agent for sewage treatment with good treatment effect in this field. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a composite treatment agent for sewage treatment and its preparation method. This composite treatment agent has good adsorption performance for heavy metals, can quickly and efficiently adsorb heavy metal ions in sewage, and can also complex organic pollutants in sewage, with good application prospects.

[0008] To achieve the above purpose, the present invention provides the following technical solutions:

[0009] A composite treatment agent for sewage, calculated by weight, includes the following raw materials:

[0010] 50-60 parts of modified diatomite, 10-20 parts of zeolite powder, 10-20 parts of polyaluminum chloride, 10-20 parts of activated carbon, 5-10 parts of shell powder, 5-10 parts of polyacrylamide, 4-8 parts of sodium dodecyl sulfate.

[0011] Preferably, a composite treatment agent for sewage, calculated by weight, includes the following raw materials:

[0012] 55 - 60 parts of modified diatomaceous earth, 15 - 20 parts of zeolite powder, 10 - 15 parts of polyaluminum chloride, 10 - 15 parts of activated carbon, 7 - 10 parts of shell powder, 5 - 8 parts of polyacrylamide, 4 - 6 parts of sodium dodecyl sulfate.

[0013] In the present invention, the zeolite powder has good adsorption capacity and has many cavities and pores; the zeolite powder can effectively adsorb the suspended solids in water that have not been flocculated and precipitated; moreover, the zeolite powder can also be adsorbed on the flocs to improve the precipitation rate of the flocs; the zeolite powder and polyaluminum chloride cooperate with each other to effectively improve the flocculation and precipitation of organic pollutants in sewage.

[0014] Preferably, the particle size of the zeolite powder is 300 - 400 μm; the particle size of the activated carbon is 100 - 200 μm; the particle size of the shell powder is 0.5 - 2 mm.

[0015] Preferably, the preparation method of the modified diatomaceous earth includes the following steps:

[0016] S1. Add diatomaceous earth into the nitric acid aqueous solution, after impregnation treatment, filter, wash, and dry to obtain acidified diatomaceous earth; then add the acidified diatomaceous earth into the sodium hydroxide solution, stir and heat, after the treatment is completed, filter, wash, dry, and calcine to obtain pretreated diatomaceous earth;

[0017] S2. Add the pretreated diatomaceous earth and Tween 20 in step S1 into the Ca(NO 3 ) 2 solution, then add the KH 2 PO 4 solution, then add nitric acid dropwise to the solution to adjust the pH to 2 - 3, after ultrasonic dispersion, carry out hydrothermal reaction, after the reaction is completed, let it stand, filter, wash, and dry to obtain composite diatomaceous earth;

[0018] S3. Add the composite diatomaceous earth in step S2 into the ethanol aqueous solution, then add γ - aminopropyltriethoxysilane, carry out stirring reaction, after the reaction is completed, filter, wash, and dry to obtain amino - modified composite diatomaceous earth;

[0019] S4. Add trans - 3 - (3 - pyridyl) acrylic acid into N,N - dimethylformamide, then add 1 - (3 - dimethylaminopropyl) - 3 - ethylcarbodiimide, stir for 30 min, then add the amino - modified composite diatomaceous earth and N - hydroxysuccinimide in step S3, carry out heating reaction, after the reaction is completed, filter, wash, and dry to obtain a solid product, then add the solid product into dimethyl sulfoxide, then add 4 - acrylamidobenzo - 18 - crown ether and ammonium persulfate, carry out a constant - temperature reaction, after the reaction is completed, filter, wash, and dry to obtain the modified diatomaceous earth.

[0020] As a biogenic siliceous rock, diatomite has a certain adsorption capacity due to its unique physical and chemical properties such as large specific surface area, many micropores and surface active groups, and negative surface charge. It is widely used to adsorb heavy metals and pigments in water bodies. However, due to the impurities in natural diatomite and the defects in its physical and chemical structure, the exertion of its adsorption capacity is restricted. Therefore, in the present invention, by modifying it, on the one hand, the pore structure can be improved to fully enhance the adsorption capacity, and on the other hand, functional functional groups are introduced to improve its ability to complex organic pollutants, significantly enhancing the comprehensive adsorption capacity of diatomite.

[0021] Preferably, in step S1, the mass concentration of the nitric acid aqueous solution is 5-8%, the temperature of the impregnation treatment is 60-70 °C, and the time is 1-2 h; the mass concentration of the sodium hydroxide solution is 5-8%, the temperature of the stirring and heating treatment is 60-70 °C, the time is 1-2 h, and the temperature of the roasting is 300-350 °C, and the time is 1-2 h.

[0022] In the present invention, the diatomite is first acidified. The acid treatment can effectively remove soluble impurities such as organic matter on the surface and in the pores of the diatomite, improve the surface and pore structure of the diatomite, increase the specific surface area, and increase the number of effective adsorption sites, which is conducive to the occurrence of adsorption; then it is alkali-washed. The reduction of the strong base restores the silanol groups on the surface of the diatomite, which not only improves the purity of the diatomite, but also increases the specific surface area and pore volume, improves the structure of the diatomite, and enhances the adsorption capacity. Then, through high-temperature calcination, the pores of the diatomite are fully expanded, and the stability of the pore structure of the diatomite is increased.

[0023] Preferably, in step S2, the concentration of the Ca(NO 3 ) 2 solution is 0.5-0.8 mol / L, the concentration of the KH 2 PO 4 solution is 0.5-0.8 mol / L, the mass-to-volume ratio of the pretreated diatomite, Tween 20, the Ca(NO 3 ) 2 solution, and the KH 2 PO 4 solution is 20 g: 1-2 g: 500-800 mL: 300-500 mL, and the temperature of the hydrothermal reaction is 140-150 °C, and the time is 3-5 h.

[0024] In the present invention, hydroxyapatite is in-situ generated on the diatomite by the hydrothermal method. Hydroxyapatite is rich in hydroxyl (-OH) and calcium phosphate ion groups, which can carry out calcium phosphate ion exchange with heavy metal ions to form complexes, thereby enhancing the adsorption capacity of the modified diatomite for heavy metal ions. At the same time, adding Tween-20 during the preparation process can effectively improve the dispersibility of the modified diatomite.

[0025] Preferably, in step S3, the mass fraction of ethanol in the aqueous ethanol solution is 60 - 70%, the mass ratio of the composite diatomite to γ-aminopropyltriethoxysilane is 50 - 60:8 - 12, the temperature of the stirring reaction is 60 - 70°C, and the time is 2 - 3 h.

[0026] In the present invention, reacting the composite diatomite with γ-aminopropyltriethoxysilane to introduce an amino group on the surface of the diatomite is beneficial to the subsequent reaction.

[0027] Preferably, the mass ratio of the amino-functionalized composite diatomite, trans-3-(3-pyridyl) acrylic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and N-hydroxysuccinimide in step S4 is 50:5 - 8:20 - 30:20 - 30, the temperature of the heating reaction is 90 - 100°C, and the time is 3 - 5 h; the mass ratio of the solid product, 4-acrylamidobenzo-18-crown ether, and ammonium persulfate is 50:6 - 9:0.1 - 0.2, the temperature of the constant-temperature reaction is 100 - 110°C, and the time is 1 - 2 h.

[0028] In the present invention, reacting the amino-functionalized composite diatomite with trans-3-(3-pyridyl) acrylic acid enables the composite diatomite to be covalently bonded to trans-3-(3-pyridyl) acrylic acid, thereby introducing a pyridine group. The lone pair electrons on the nitrogen atom in the pyridine group can undergo a coordination interaction with the empty orbital of the metal ion to form a coordination bond with the metal ion, thereby improving the adsorption of the modified diatomite on heavy metal ions. Subsequently, reacting 4-acrylamidobenzo-18-crown ether with the diatomite introduces a crown ether and an amide group on the diatomite. The oxygen atom and nitrogen atom in the amide group both have lone pair electrons and can act as ligands to form coordination bonds with heavy metal ions, and the lone pair electrons on the oxygen atom in the crown ether form a coordination bond with the metal ion. The two act synergistically with the pyridine group, significantly improving the adsorption of the diatomite on heavy metal ions. At the same time, the benzene ring in the crown ether can interact with aromatic organic compounds in the sewage through π-π stacking, and the alkyl chain segment in the crown ether can have a hydrophobic interaction with hydrophobic organic molecules, thereby significantly improving the removal of organic pollutants in the sewage by the modified diatomite and enhancing the comprehensive performance of the modified diatomite in treating sewage.

[0029] The present invention also protects a preparation method of the composite treatment agent for sewage as described above, comprising the following steps:

[0030] Weigh the raw materials according to the formula, mix and grind the modified diatomite, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, sodium dodecyl sulfate, and ethanol solution, and dry at 80 - 90°C to obtain the composite treatment agent.

[0031] The present invention also protects the application of a composite treatment agent for sewage as described above in treating chemical industrial sewage.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The composite treatment agent for sewage treatment provided by the present invention is prepared by compounding and mixing modified diatomite, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, and sodium dodecyl sulfate in a specific proportion. Modified diatomite, zeolite powder, and activated carbon have good abilities to adsorb heavy metals and organic pollutants. Polyaluminum chloride has a sedimentation effect, and sodium dodecyl sulfate has good dispersibility. Polacrylamide is used as a flocculant to remove suspended solids and colloids in water. Due to its large surface area and high porosity, shell powder can effectively adsorb heavy metal ions in water, making the obtained composite treatment agent have good adsorption properties, capable of quickly and efficiently adsorbing heavy metal ions in sewage, and at the same time, it can also complex organic pollutants in sewage, showing good application prospects.

[0034] (2) For the composite treatment agent for sewage treatment provided by the present invention, the added modified diatomite is acidified - alkali washed - calcined, which improves the purity of diatomite, increases the specific surface area and pore volume, improves the structure of diatomite, and enhances the adsorption capacity. The pore channels of diatomite are fully expanded, and the stability of the pore channel structure of diatomite is increased. Subsequently, hydroxyapatite is in-situ generated on diatomite by hydrothermal method. Hydroxyapatite is rich in hydroxyl groups (-OH) and calcium and phosphorus ion groups, which can form complexes with heavy metal ions through calcium and phosphorus ion exchange, thereby improving the adsorption capacity of modified diatomite for heavy metal ions. At the same time, adding Tween - 20 during the preparation process can effectively improve the dispersibility of modified diatomite. Then, by chemical reaction, trans - 3-(3 - pyridyl) acrylic acid and 4 - acrylamidobenzo - 18 - crown ether are grafted onto diatomite in the form of covalent bonds, thereby introducing pyridine groups, crown ether groups, and amide groups. The pyridine group contains a nitrogen atom, and the lone pair electrons on the nitrogen atom can coordinate with the empty orbitals of metal ions to form coordination bonds, thus improving the adsorption of modified diatomite for heavy metal ions. The oxygen and nitrogen atoms in the amide group both have lone pair electrons, which can act as ligands to form coordination bonds with heavy metal ions, and the lone pair electrons on the oxygen atom in the crown ether form coordination bonds with metal ions. The two work synergistically with the pyridine group to significantly improve the adsorption of diatomite for heavy metal ions. At the same time, the benzene ring in the crown ether can interact with aromatic organic compounds in sewage through π - π stacking, and the alkyl chain segments in the crown ether can have hydrophobic interactions with hydrophobic organic molecules, thereby significantly improving the removal of organic pollutants in sewage by modified diatomite and enhancing the comprehensive performance of modified diatomite in treating sewage.

[0035] (3) The composite treatment agent for sewage treatment provided by the present invention prepares modified diatomaceous earth through a specific method, grafts trans-3-(3-pyridyl) acrylic acid and 4-acrylamidobenzo-18-crown ether onto the diatomaceous earth in the form of covalent bonds, avoids secondary pollution caused by the shedding of organic small molecules during sewage treatment, improves the treatment efficiency of the composite treatment agent, and expands the application field. Detailed implementation mode

[0036] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0037] In the present invention, the zeolite powder is purchased from Zhongzheng Perlite Factory in Pingqiao District, Xinyang City, with a particle size of 300-400 μm; the activated carbon is purchased from Chengde Tianyuan Activated Carbon Co., Ltd., with a particle size of 100-200 μm; the shell powder is purchased from Jiayuan Mineral Products Processing Factory in Lingshou County, with a particle size of 0.5-2 mm; the polyaluminum chloride is purchased from Gongyi Shui Zhiyuan Water Purification Materials Co., Ltd., with an alumina content of 28%; the polyacrylamide is purchased from Wuxi Lanbo Chemical Co., Ltd., with a molecular weight of 8 million.

[0038] Example 1

[0039] A composite treatment agent for sewage, by weight, includes the following raw materials:

[0040] 55 parts of modified diatomaceous earth, 15 parts of zeolite powder, 15 parts of polyaluminum chloride, 15 parts of activated carbon, 7 parts of shell powder, 8 parts of polyacrylamide, and 6 parts of sodium dodecyl sulfate.

[0041] Among them, the preparation method of the modified diatomaceous earth includes the following steps:

[0042] S1. Add 100 g of diatomaceous earth to 1 L of nitric acid aqueous solution with a mass concentration of 7%, impregnate at 65 °C for 1.5 h, then filter, wash, and dry to obtain acidified diatomaceous earth; then add 100 g of acidified diatomaceous earth to a sodium hydroxide solution with a mass concentration of 7%, stir and heat at 65 °C for 1.5 h, after the treatment is completed, filter, wash, and dry, and calcine at 330 °C for 1.5 h to obtain pretreated diatomaceous earth;

[0043] S2. Add 20 g of the pretreated diatomaceous earth and 1.5 g of Tween 20 in step S1 to 700 mL of a solution of Ca(NO 3 ) 2 solution, and then add 400 mL of a KH solution with a concentration of 0.7 mol / L2 PO 4 solution, and then 7% nitric acid by mass was added dropwise to the solution to adjust the pH to 2.5. After ultrasonic dispersion for 30 min, hydrothermal reaction was carried out at 145 °C for 4 h. After the reaction, it was left standing, filtered, washed, and dried to obtain composite diatomite;

[0044] S3. 55 g of the composite diatomite in step S2 was added to 1 L of an ethanol aqueous solution (mass fraction of ethanol was 65%), and then 10 g of γ-aminopropyltriethoxysilane was added. Stirring reaction was carried out at 65 °C for 2.5 h. After the reaction was completed, it was filtered, washed, and dried to obtain amino-functionalized composite diatomite;

[0045] S4. 7 g of trans-3-(3-pyridyl) acrylic acid was added to 800 mL of N,N-dimethylformamide, and then 25 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide was added. After stirring for 30 min, 50 g of the amino-functionalized composite diatomite and 25 g of N-hydroxysuccinimide in step S3 were added. The reaction was carried out at 95 °C for 4 h. After the reaction was completed, it was filtered, washed, and dried to obtain a solid product. Subsequently, 50 g of the solid product was added to 800 mL of dimethyl sulfoxide, and then 8 g of 4-acrylamidobenzo-18-crown ether and 0.15 g of ammonium persulfate were added. The reaction was carried out at a constant temperature of 105 °C for 1.5 h. After the reaction was completed, it was filtered, washed, and dried to obtain the modified diatomite.

[0046] A preparation method of a composite treatment agent for sewage, comprising the following steps:

[0047] Weigh the raw materials according to the formula, mix the modified diatomite, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, and sodium dodecyl sulfate evenly, add an equal mass of ethanol solution (mass concentration of 50%) and mix and grind for 30 min, and dry at 85 °C to obtain the composite treatment agent.

[0048] Example 2

[0049] A composite treatment agent for sewage, by weight, comprises the following raw materials:

[0050] 55 parts of modified diatomite, 15 parts of zeolite powder, 15 parts of polyaluminum chloride, 15 parts of activated carbon, 8 parts of shell powder, 7 parts of polyacrylamide, and 6 parts of sodium dodecyl sulfate.

[0051] Among them, the preparation method of the modified diatomite comprises the following steps:

[0052] S1. Add 100 g of diatomaceous earth to 1 L of nitric acid aqueous solution with a mass concentration of 6%, impregnate at 65 °C for 1.5 h, then filter, wash, and dry to obtain acidified diatomaceous earth; then add 100 g of acidified diatomaceous earth to a sodium hydroxide solution with a mass concentration of 6%, stir and heat at 65 °C for 1.5 h, after the treatment is completed, filter, wash, and dry, and calcine at 320 °C for 1.5 h to obtain pretreated diatomaceous earth;

[0053] S2. Add 20 g of the pretreated diatomaceous earth and 1.5 g of Tween 20 in step S1 to 600 mL of a Ca(NO 3 ) 2 solution, then add 400 mL of a KH 2 PO 4 solution, then add nitric acid with a mass concentration of 6% dropwise to the solution to adjust the pH to 2.5, ultrasonically disperse for 30 min, and then carry out hydrothermal reaction at 145 °C for 4 h. After the reaction is completed, let it stand, filter, wash, and dry to obtain composite diatomaceous earth;

[0054] S3. Add 55 g of the composite diatomaceous earth in step S2 to 1 L of ethanol aqueous solution (the mass fraction of ethanol is 65%), then add 10 g of γ-aminopropyltriethoxysilane, stir and react at 65 °C for 2.5 h. After the reaction is completed, filter, wash, and dry to obtain amino-functionalized composite diatomaceous earth;

[0055] S4. Add 6 g of trans-3-(3-pyridyl) acrylic acid to 800 mL of N,N-dimethylformamide, then add 23 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, stir for 30 min, then add 50 g of the amino-functionalized composite diatomaceous earth and 23 g of N-hydroxysuccinimide in step S3, react at 95 °C for 4 h. After the reaction is completed, filter, wash, and dry to obtain a solid product. Then add 50 g of the solid product to 800 mL of dimethyl sulfoxide, then add 7 g of 4-acrylamidobenzo-18-crown ether and 0.15 g of ammonium persulfate, carry out a constant temperature reaction at 105 °C for 1.5 h. After the reaction is completed, filter, wash, and dry to obtain the modified diatomaceous earth.

[0056] A preparation method of a composite treatment agent for sewage, comprising the following steps:

[0057] Weigh the raw materials according to the formula, mix the modified diatomaceous earth, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, and sodium dodecyl sulfate evenly, add an equal mass of ethanol solution (mass concentration of 50%) and mix and grind for 30 min, and dry at 85 °C to obtain the composite treatment agent.

[0058] Example 3

[0059] A composite treatment agent for sewage, by weight, comprises the following raw materials:

[0060] 50 parts of modified diatomite, 10 parts of zeolite powder, 10 parts of polyaluminum chloride, 10 parts of activated carbon, 5 parts of shell powder, 5 parts of polyacrylamide, and 4 parts of sodium dodecyl sulfate.

[0061] Among them, the preparation method of the modified diatomite comprises the following steps:

[0062] S1. Add 100 g of diatomite to 1 L of nitric acid aqueous solution with a mass concentration of 5%, impregnate at 60 °C for 2 h, then filter, wash, and dry to obtain acidified diatomite; then add 100 g of acidified diatomite to a sodium hydroxide solution with a mass concentration of 5%, stir and heat at 60 °C for 2 h, after the treatment is completed, filter, wash, and dry, and calcine at 300 °C for 2 h to obtain pretreated diatomite;

[0063] S2. Add 20 g of the pretreated diatomite and 1 g of Tween 20 in step S1 to 500 mL of a Ca(NO 3 ) 2 solution, then add 300 mL of a KH 2 PO 4 solution, then add nitric acid with a mass concentration of 5% dropwise to the solution to adjust the pH to 3, ultrasonically disperse for 30 min, and then carry out hydrothermal reaction at 140 °C for 5 h. After the reaction is completed, let it stand, filter, wash, and dry to obtain composite diatomite;

[0064] S3. Add 50 g of the composite diatomite in step S2 to 1 L of ethanol aqueous solution (the mass fraction of ethanol is 60%), then add 8 g of γ-aminopropyltriethoxysilane, stir and react at 60 °C for 3 h. After the reaction is completed, filter, wash, and dry to obtain amino-functionalized composite diatomite;

[0065] S4. Add 5 g of trans-3-(3-pyridyl) acrylic acid to 800 mL of N,N-dimethylformamide, then add 20 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, stir for 30 min, then add 50 g of the amino-functionalized composite diatomite and 20 g of N-hydroxysuccinimide in step S3, react at 90 °C for 5 h. After the reaction is completed, filter, wash, and dry to obtain a solid product. Then add 50 g of the solid product to 800 mL of dimethyl sulfoxide, then add 6 g of 4-acrylamidobenzo-18-crown ether and 0.1 g of ammonium persulfate, react at 100 °C under constant temperature for 2 h. After the reaction is completed, filter, wash, and dry to obtain the modified diatomite.

[0066] A preparation method of a composite treatment agent for sewage, comprises the following steps:

[0067] Weigh the raw materials according to the formula. Mix the modified diatomite, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, and sodium dodecyl sulfate evenly, add an equal mass of ethanol solution (mass concentration 50%), mix and grind for 30 min, and dry at 80 °C to obtain the composite treatment agent.

[0068] Example 4

[0069] A composite treatment agent for sewage, by weight, comprises the following raw materials:

[0070] 60 parts of modified diatomite, 20 parts of zeolite powder, 20 parts of polyaluminum chloride, 20 parts of activated carbon, 10 parts of shell powder, 10 parts of polyacrylamide, and 8 parts of sodium dodecyl sulfate.

[0071] Among them, the preparation method of the modified diatomite comprises the following steps:

[0072] S1. Add 100 g of diatomite to 1 L of nitric acid aqueous solution with a mass concentration of 8%, impregnate at 70 °C for 1 h, then filter, wash, and dry to obtain acidified diatomite; then add 100 g of acidified diatomite to a sodium hydroxide solution with a mass concentration of 8%, stir and heat at 70 °C for 1 h, after the treatment is completed, filter, wash, and dry, and calcine at 350 °C for 1 h to obtain pretreated diatomite;

[0073] S2. Add 20 g of the pretreated diatomite and 2 g of Tween 20 in step S1 to 800 mL of a solution with a concentration of 0.5 mol / L of Ca(NO 3 ) 2 solution, then add 500 mL of a solution with a concentration of 0.5 mol / L of KH 2 PO 4 solution, then add nitric acid with a mass concentration of 8% dropwise to the solution to adjust the pH to 2, ultrasonically disperse for 30 min, and then carry out hydrothermal reaction at 150 °C for 3 h. After the reaction is completed, let it stand, filter, wash, and dry to obtain composite diatomite;

[0074] S3. Add 60 g of the composite diatomite in step S2 to 1 L of ethanol aqueous solution (mass fraction of ethanol is 70%), then add 12 g of γ-aminopropyltriethoxysilane, stir and react at 70 °C for 2 h, after the reaction is completed, filter, wash, and dry to obtain amino-functionalized composite diatomite;

[0075] S4. Add 8 g of trans-3-(3-pyridyl) acrylic acid to 800 mL of N,N-dimethylformamide, then add 30 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide. After stirring for 30 min, add 50 g of the amino-functionalized composite diatomaceous earth and 30 g of N-hydroxysuccinimide from step S3, and react at 100 °C for 3 h. After the reaction is completed, filter, wash, and dry to obtain a solid product. Subsequently, add 50 g of the solid product to 800 mL of dimethyl sulfoxide, then add 9 g of 4-acrylamidobenzo-18-crown ether and 0.2 g of ammonium persulfate, and react at a constant temperature of 110 °C for 1 h. After the reaction is completed, filter, wash, and dry to obtain the modified diatomaceous earth.

[0076] A preparation method of a composite treatment agent for sewage, comprising the following steps:

[0077] Weigh the raw materials according to the formula, mix the modified diatomaceous earth, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, and sodium dodecyl sulfate evenly, add an equal mass of ethanol solution (mass concentration of 50%) and mix and grind for 30 min, and dry at 90 °C to obtain the composite treatment agent.

[0078] Comparative Example 1

[0079] A composite treatment agent for sewage, by weight, comprises the following raw materials:

[0080] 55 parts of modified diatomaceous earth, 15 parts of zeolite powder, 15 parts of polyaluminum chloride, 15 parts of activated carbon, 7 parts of shell powder, 8 parts of polyacrylamide, and 6 parts of sodium dodecyl sulfate.

[0081] Among them, the preparation method of the modified diatomaceous earth comprises the following steps:

[0082] S1. Add 100 g of diatomaceous earth to 1 L of nitric acid aqueous solution with a mass concentration of 7%, impregnate at 65 °C for 1.5 h, then filter, wash, and dry to obtain acidified diatomaceous earth; subsequently, add 100 g of acidified diatomaceous earth to a sodium hydroxide solution with a mass concentration of 7%, stir and heat at 65 °C for 1.5 h, after the treatment is completed, filter, wash, and dry, and calcine at 330 °C for 1.5 h to obtain pretreated diatomaceous earth;

[0083] S2. Add 20 g of the pretreated diatomaceous earth and 1.5 g of Tween 20 from step S1 to 700 mL of a solution of Ca(NO 3 ) 2 solution, then add 400 mL of a KH 2 PO 4A solution was prepared, and then 7% nitric acid by mass concentration was added dropwise to the solution to adjust the pH to 2.5. After ultrasonic dispersion for 30 min, hydrothermal reaction was carried out at 145 °C for 4 h. After the reaction, it was allowed to stand, filtered, washed, and dried to obtain composite diatomite;

[0084] S3. Add 55 g of the composite diatomite in step S2 to 1 L of an ethanol aqueous solution (the mass fraction of ethanol is 65%), then add 10 g of γ-aminopropyltriethoxysilane, and stir and react at 65 °C for 2.5 h. After the reaction is completed, filter, wash, and dry to obtain amino-functionalized composite diatomite;

[0085] S4. Add 7 g of trans-3-(3-pyridyl) acrylic acid to 800 mL of N,N-dimethylformamide, then add 25 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide. After stirring for 30 min, add 50 g of the amino-functionalized composite diatomite and 25 g of N-hydroxysuccinimide in step S3, and react at 95 °C for 4 h. After the reaction is completed, filter, wash, and dry to obtain the modified diatomite.

[0086] A preparation method of a composite treatment agent for sewage includes the following steps:

[0087] Weigh the raw materials according to the formula, mix the modified diatomite, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, and sodium dodecyl sulfate evenly, add an equal mass of ethanol solution (mass concentration of 50%) and mix and grind for 30 min, and dry at 85 °C to obtain the composite treatment agent.

[0088] Compared with Example 1, 4-acrylamidobenzo-18-crown ether was not introduced onto the diatomite in this comparative example.

[0089] Comparative Example 2

[0090] A composite treatment agent for sewage, by weight, includes the following raw materials:

[0091] 55 parts of modified diatomite, 15 parts of zeolite powder, 15 parts of polyaluminum chloride, 15 parts of activated carbon, 7 parts of shell powder, 8 parts of polyacrylamide, and 6 parts of sodium dodecyl sulfate.

[0092] Among them, the preparation method of the modified diatomite includes the following steps:

[0093] S1. Add 100 g of diatomite to 1 L of a 7% nitric acid aqueous solution, impregnate at 65 °C for 1.5 h, then filter, wash, and dry to obtain acidified diatomite; then add 100 g of acidified diatomite to a 7% sodium hydroxide solution, stir and heat at 65 °C for 1.5 h. After the treatment is completed, filter, wash, and dry, and calcine at 330 °C for 1.5 h to obtain pretreated diatomite;

[0094] S2. Add 20 g of pretreated diatomaceous earth and 1.5 g of Tween 20 from step S1 into 700 mL of a Ca(NO 3 ) 2 solution with a concentration of 0.6 mol / L. Subsequently, add 400 mL of a KH 2 PO 4 solution with a concentration of 0.7 mol / L. Then, add nitric acid with a mass concentration of 7% dropwise to the solution to adjust the pH to 2.5. After ultrasonic dispersion for 30 min, perform a hydrothermal reaction at 145 °C for 4 h. After the reaction is completed, let it stand, filter, wash, and dry to obtain the composite diatomaceous earth;

[0095] S3. Add 55 g of the composite diatomaceous earth from step S2 into 1 L of an ethanol aqueous solution (the mass fraction of ethanol is 65%). Then, add 10 g of γ-aminopropyltriethoxysilane and stir and react at 65 °C for 2.5 h. After the reaction is completed, filter, wash, and dry to obtain the modified diatomaceous earth.

[0096] A preparation method of a composite treatment agent for sewage, comprising the following steps:

[0097] Weigh the raw materials according to the formula. Mix the modified diatomaceous earth, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, and sodium dodecyl sulfate evenly. Add an equal mass of an ethanol solution (mass concentration of 50%) and mix and grind for 30 min. Dry at 85 °C to obtain the composite treatment agent.

[0098] Compared with Example 1, in this comparative example, trans-3-(3-pyridyl) acrylic acid and 4-acrylamidobenzo-18-crown ether were not introduced onto the diatomaceous earth.

[0099] Respectively detect the adsorption performance of the composite treatment agents prepared in Examples 1-4 and Comparative Examples 1-2 for sewage with complex components, as follows: Prepare simulated wastewater. The concentrations of Cd 2+ , Cu 2+ , and Pb 2+ in the wastewater are all 500 mg / L, the methyl orange content is 100 mg / L, and the rhodamine B content is 100 mg / L. Take 6 500-mL conical flasks. Add 200 mL of simulated wastewater to each conical flask. Then, add 1 g of the composite treatment agents prepared in Examples 1-4 and Comparative Examples 1-2 respectively. Place them in a constant-temperature shaker and oscillate under natural light. Set the shaker temperature to 25 °C, the rotation speed to 250 rpm, and the oscillation time to 1 h. After the oscillation is completed, filter the solution through a microporous filter membrane, and then detect the concentrations of various pollutants in the solution. Take the average value after testing 3 times and calculate the removal rate. The test results are shown in Table 1 below:

[0100] Table 1 Performance test results of each group of composite treatment agents

[0101]

[0102] As can be seen from Table 1, the composite treatment agent for sewage prepared by the present invention has good adsorption properties for heavy metals and organic pollutants, can rapidly and efficiently adsorb heavy metal ions and organic pollutants in sewage, and has good application prospects.

[0103] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite treatment agent for sewage, characterized in that: By weight, it includes the following raw materials: 50-60 parts of modified diatomaceous earth, 10-20 parts of zeolite powder, 10-20 parts of polyaluminium chloride, 10-20 parts of activated carbon, 5-10 parts of shell powder, 5-10 parts of polyacrylamide and 4-8 parts of sodium dodecyl sulfate.

2. The composite treatment agent for sewage according to claim 1, characterized in that: By weight, it includes the following raw materials: 55-60 parts of modified diatomaceous earth, 15-20 parts of zeolite powder, 10-15 parts of polyaluminium chloride, 10-15 parts of activated carbon, 7-10 parts of shell powder, 5-8 parts of polyacrylamide and 4-6 parts of sodium dodecyl sulfate.

3. The composite treatment agent for sewage according to claim 1, characterized in that: The particle size of the zeolite powder is 300-400 μm; the particle size of the activated carbon is 100-200 μm; and the particle size of the shell powder is 0.5-2 mm.

4. The composite treatment agent for sewage according to claim 1, characterized in that: The preparation method of the modified diatomite comprises the following steps: S1, adding diatomaceous earth to a nitric acid aqueous solution, filtering, washing, and drying after immersion treatment to obtain acidified diatomaceous earth; then adding the acidified diatomaceous earth to a sodium hydroxide solution, stirring and heating treatment, filtering, washing, drying, and roasting after the treatment to obtain pretreated diatomaceous earth; S2, adding the pretreated diatomaceous earth and Tween 20 in step S1 to a Ca(NO3)2 solution, then adding a KH2PO4 solution, then dropping nitric acid into the solution, adjusting the pH to 2-3, performing a hydrothermal reaction after ultrasonic dispersion, and after the reaction, standing, filtering, washing, and drying to obtain a composite diatomaceous earth; S3, adding the composite diatomaceous earth in step S2 to an ethanol aqueous solution, then adding γ-aminopropyltriethoxysilane, stirring to react, filtering, washing, and drying after the reaction is completed to obtain an amino composite diatomaceous earth; S4, add trans-3-(3-pyridyl)allylic acid to N,N-dimethylformamide, then add 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, stir for 30 minutes, add the aminated composite diatomite and N-hydroxysuccinimide in step S3, and heat to react. After the reaction is completed, filter, wash, and dry to obtain a solid product. Subsequently, add the solid product to dimethyl sulfoxide, then add 4-acrylamide benzo-18-crown ether and ammonium persulfate, and react at a constant temperature. After the reaction is completed, filter, wash, and dry to obtain the modified diatomite.

5. The composite treatment agent for sewage according to claim 1, characterized in that: The mass concentration of the nitric acid aqueous solution in step S1 is 5-8%, the temperature of the immersion treatment is 60-70°C, and the time is 1-2h; the mass concentration of the sodium hydroxide solution is 5-8%, the temperature of the stirring and heating treatment is 60-70°C, and the time is 1-2h, and the temperature of the roasting is 300-350°C, and the time is 1-2h.

6. The composite treatment agent for sewage according to claim 1, characterized in that: The concentration of the Ca(NO3)2 solution in step S2 is 0.5-0.8 mol / L, the concentration of the KH2PO4 solution is 0.5-0.8 mol / L, the mass volume ratio of the pretreated diatomaceous earth, Tween 20, Ca(NO3)2 solution, and KH2PO4 solution is 20g:1-2g:500-800mL:300-500mL, the temperature of the hydrothermal reaction is 140-150°C, and the time is 3-5h.

7. The composite treatment agent for sewage according to claim 1, characterized in that: In step S3, the mass fraction of ethanol in the ethanol aqueous solution is 60-70%, the mass ratio of the composite diatomite and γ-aminopropyltriethoxysilane is 50-60:8-12, the temperature of the stirring reaction is 60-70° C., and the time is 2-3 hours.

8. The composite treatment agent for sewage according to claim 1, characterized in that: In step S4, the mass ratio of the aminated composite diatomite, trans-3-(3-pyridyl)allylic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and N-hydroxysuccinimide is 50:5-8:20-30:20-30, the temperature of the heating reaction is 90-100°C, and the time is 3-5h; the mass ratio of the solid product, 4-acrylamidebenzo-18-crown ether, and ammonium persulfate is 50:6-9:0.1-0.2, the temperature of the isothermal reaction is 100-110°C, and the time is 1-2h.

9. A method for preparing a composite treatment agent for sewage according to any one of claims 1 to 8, characterized in that: The following steps are involved: The raw materials are weighed according to the formula, and the modified diatomaceous earth, zeolite powder, polyaluminium chloride, activated carbon, shell powder, polyacrylamide, sodium dodecyl sulfate and ethanol solution are mixed and ground, and dried at 80-90° C. to obtain the composite treatment agent.

10. Use of the composite treating agent for sewage as claimed in any one of claims 1 to 8 in treating chemical sewage.

Images